[Left] [Up] [Right] NASA's Global Precipitation Measurement (GPM) System [Left] [Up] [Right]

The NASA GPM project contains elements of the major challenges facing the practising systems engineer:

Science Mission [Spacecraft Image1]

Provide satellite coverage and sampling strategy to (Adams, 2001):

  • Improve probability of detection of extreme rain events. Coverage region: 90 N to 90 S latitude. Goal: 3 hour maximum revisit interval.
  • Better understand the horizontal and vertical structure of rainfall and its microphysical elements.
  • Provide enough sampling to reduce the uncertainty in predictions for short-term accumulations.
  • Extend scientific and societal applications (e.g., improved water resources and infrastructure planning --> better policies for sustainable development).

Systems Architecture

Form rain measuring constellation using co-op satellites from other programs suitable passive microwave radiometers dedicated to GPM mission:

  • Core Satellites
    Provide instruments for cloud physics research and calibration of radiometers on constellation satellites.
    • Dual frequency radar and multi-frequecy radiometer.
    • TRMM-like spacecraft at 400-500 km altitude.
  • Constellation Satellites
    • Multiple satellites with microwave radiometers.
    • Aggregate revisit time -- 3 hour goal.
    • Approximate altitude 600 km.
  • Precipitation Validation Sites
    • Global ground based rain measurement.
  • Global Precipitation Processing Center
    • Produces Global precipitation data products as defined by the GPM partners.
[Spacecraft Image1]

Program Budget, Participants, and Schedule

  • Need a minimum of 7 satellites for the system to work.
  • Budget. NASA only has enough money to pay for 2 of them.

GPM performance depends on sucessful partnerships -- space segment; ground segment; validation segment; research segment.

  • Current project partners: S. Korea, Japan.
  • Potential partners for constellation satellites: Canada, Australia, France, Italy, United Kingdom, China, India....
  • Partner satellites (e.g., EuroGPM-1, Euro-GPM-2) are scheduled for launch 2008-2010.
  • Duration. At least through 2018.

GPM Trade Space

The GPM trade space includes:

  • Science requirements and partnership development.
  • Systems engineering and measures of systems effectiveness.
  • Mission architecture.
  • Measurement approach -- radar and radiometers.
  • Ground and data systems.
  • Progrommatic considerations.

Section 2-1: April, 2003. [Left] [Up] [Right]